Apparatus for molding tongue and groove concrete slabs



H. B. HEMB July 28, 1959 APPARATUS FOR MOLDING TONGUE AND GROOVE CONCRETE SLABS Filed Aug. 13, 1956 4 Sheets-Sheet 1 A tt INVENTOR.

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APPARATUS FOR MOLDING TONGUE AND GROOVE CONCRETE SLABS Filed Aug. 13, 1956 4 Sheets-Sheet 2 I I I IN V EN TOR. Male 98. 35 67/725- WFM July 28, 1959 Filed Aug. 13, 1956 H. B. HEMB APPARATUS FOR MOLDING TONGUE AND GROOVE CONCRETE SLABS 4 Sheets-Sheet 3 INVENTOR.

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APPARATUS FOR MOLDING TONGUE AND GROOVE CONCRETE SLABS Filed Aug. 13, 1956 A 4 Sheets-Sheet 4 I r I I I A; 23 5 A9 36 40 I3 /4 /6 5/45 Fz'y. A2

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44 flcz/ad Bf/e mg' BY Fij- /& W $23M APPARATUS FOR MOLDING TONGUE AND GROOVE CONCRETE SLA BS Harald B. Hemb, Glencoe, Ill.

.Application August 13, 1956, Serial No. 603,624

1 Claim. (Cl. 25-121) This invention relates to apparatus for molding concrete slabs having tongue and groove construction on some or all of the edges thereof, and concrete slabs having score grooves for breaking purposes, and comprising a plurality of edgewise mounted, open top molds clamped together, the mold-supporting part of the apparatus being rapidly vibrated while the wet concrete mix is being poured into the mold spaces through the open top edges thereof.

The present invention is an improvement over that of my United States Letter Patent No. 2,545,029, granted March 13, 1951, in which patent the plates are formed with ribs on one face only, and the slabs are formed with straight, flat edges, easily removable from the molds after the concrete is hardened. As is obvious, it would be impossible, without the benefit of the present invention, to make concrete slabs having tongue and groove edges in the apparatus of my said prior patent, for the reason that the hardened concrete behind the inwardly protruding portions at the edges of the mold cavity would prevent withdrawal ofthe hardened slab from the mold without destruction of the mold.

Precast concrete slabs of the nature of those here under discussion are thin compared with their width and length. T make such slabs in molds lying horizontal would be extremely slow, and would require considerable space, as only one thickness of slab could be made at a time, thus resulting in concrete slabs that would not have the desired uniformity, and would have to be sold at a higher price because of the time and labor involved. In order tobe able to make tongue and groove concrete slabs in the type of apparatus disclosed in my said prior patent, I have provided a novel form of mold units to enable quick and easy withdrawal of the slabs from the molds after hardening, without injury to the molds, and to facilitate the quick assembly of the multiple mold units in preparing the apparatus for further operation.

Among the objects of myinvention are: to provide a new and improved apparatus for molding concrete slabs; to provide a novel construction of molds for molding concrete slabs having tongue and groove edges; to provide a plurality of flat plates each having fixed to one side part of the mold on one face and part of the mold on the other face to form mold units, and a groove-forming member separable from the mold to enable removal of a hardened slab from the mold when the units are separated from each other; to provide in a mold for tongue and groove concrete slabs, a novel removable groove-forming member; to provide a plurality of novel mold units for making tongue and groove concrete slabs, which units may be clamped together, vibrated and filled, and when separated after the concrete is hardened will enable the tongue andgroove slabs to be easily removed from the molds; to provide apparatus for molding concrete slabs having score grooves for breaking purposes; and such further' objects, advantages and capabilities, inherently possessed by my invention, as will later more fully appear.

I My invention further resides in theconstruction, combination, and arrangement of parts illustrated in the accompanying drawings, and while I have shown therein preferred embodiments I wish it understood that the same are susceptible of modification and change without departing from the spirit of my invention.

In'the drawings:

--Fig. l is aside elevation of an apparatus embodying my invention, but omitting the vibrating motor and showing the driving belt in section.

Fig. 2. is a top plan view, on a large scale than Fig. 1, of three of the mold units, partly broken away, in assembled relationship.

Fig. 3 is a top plan view, partly broken away, of a single mold unit, in position to be moved against the adjacent side of Fig. 2.

Fig. 4 is a side elevation, partly broken away, looking toward the lower side face of Fig. 3. v

Fig. 5 is'a side elevation, partly broken away, looking toward the upper side face of Fig. 3.

Fig. 6 is an edge elevation, partly broken away, looking toward the right hand edge of Fig. 2.

Fig. 7 is a vertical transverse section, partly broken away, on the line 7-7 of Fig. 2.

Fig. 8 is an edge elevation, partly broken away, looking toward the right hand edge of Fig. 3.

Fig. 9 is a top plan view, partly broken away, looking down upon four slabs arranged in assembled position on the ground, with their adjacent tongue and groove edges interengaged.

Fig. 10 is an edge elevation, partly broken away, looking toward the right hand edge of Fig. 9.

Fig. 11 is an edge elevation, partly broken away, looking. toward the bottom edge of Fig. 9.

i .Fig. 12 is a top plan view, partly broken away, of one mold unit separated from an adjacent portion of an adja- 1 cent mold unit, in position with the latter separated from Fig-l3 is a vertical transverse section, partly broken face a number of vertically and horizontally extending ribs angular in cross-section to form part of the mold, and having fixed to its opposite side face a number of vertically and horizontally extending ribs'angular in cross-section, the ribs on one face of one plate fitting into those on the adjacent face of the adjacent plate to form tongue and groove edges for concrete slabs; to pro-. vide molds for tongue and groove concrete slabs, having a plurality of plates each having part of the mold on one face and part of the mold on the opposite face to form a mold unit, so that the units maybe clamped together, the molds vibrated and filled with' wet cement, and the units separated from each other when the cement is hardened, to enable easy removal ofjthe tongue and groove slab from the mold; to provide molds for tongue and groove concrete slabs, having a plurality of plates each having theaformer after the molded concrete slab has hardened, andshowing score ribs for forming grooves to enable the slabrto be broken into smaller portions when desired.

away, on the line 13-13 of Fig. 12.

,Fig. 14 is a vertical transverse Section, partly broken away, on the line 1414 of Fig. 12. FxFig. 15 is a vertical transverse section, partly broken away, on the line 15-15 of Fig. 12.

Fig. '16 is a face elevation of a slab made in the mold of Figs. 12-15, and showing score grooves: to enable breaking the slab into smaller portions when desired.

:Fig. 17 is an edge view looking toward the right hand of a modified form of single mold unit, showing wooden ribs secured to the main plates by bolts, nails, and the like.

Fig. 20 is a view similar to Fig. 19, but looking toward the near end of the single unit of Fig. 19.

In the form shown in the drawings for illustrative purposes, the present apparatus comprises generally a plurality of mold units clamped in vertical edgewise position in a frame having laterally spaced apart supportingbase members 1 upon which the mold units rest, vertically extending braced members 2 atthe rear end for receiving the thrust when the mold units are clamped together, a plurality of vertical shafts 3 rotatably mounted in the base members at the front end of the frame, each of said shafts having a plurality of cams 4 and a handle 5 fixed thereto, the handle enabling manual rotation of the shafts to move the cams for clamping the mold units in the frame. Extending longitudinally from front to rear of the frame, and resting upon the top edges of the mold units, are a plurality of tension rods or cables 6, each having at its front end an eyelet or ring 7 to be slipped over the top end of its respective shaft 3 and having at its rear end a hook 8 to be hooked over a cross bar 9, so that when the frame is filled with properly assembled mold units and the rods or cables 6 in place, rotation of the shafts 3 to tighten the cams 4 against the end plate 10 'at the front end, will tightly and firmly clamp a large number of mold units in place in the frame. The frame is. resiliently mounted upon a plurality of coil springs 11, and has mounted upon its lower portion a shaft 12 having fixed to rotate therewith eccentrically mounted weights 13, so that when shaft 12 is rotated by belt 14, from any suitable source of motor power, at a sufficiently high speed, the assembled molds will be vibrated while the wet concrete is being poured into the molds through theiropen tops. For a more detailed description of the clamping and vibratingapparatus referred to generally above, see my said prior Patent 2,545,029.

Instead of plates having ribs on one face only for forming slabs with flat edges as in my said prior patent, I have in the present invention provided plates each having ribs specially arranged and fixed on both faces for forming concrete slabs having tongues and grooves on their edges. Each of the plates 15,, with said ribs on both faces, forms a mold unit as will be understood in Figs. 3 and 8. These mold units, except when clamped together in the vibrating frame, are separate from each other, so that they can be placed face to face against each other in the frame and clamped, to form open-top molds, and separated from each other when unclarnped, after the concrete is hardened, to enable easy removal of the tongue and groove slabs from the molds.

Referring in detail to' Figs. 3-5 and 8, each of these units comprises a plate 15, formed of any suitable material, preferably steel, and of a size to permit the molding of any desired number of slabs, two being provided for, forillustrative purposes, in the drawings of the present application. Secured to the upper faceof each of plates 15, as viewed in Fig. 3, at a slight distance inwardly of the right hand edge thereof, is a metal rib 16, of triangular cross-section, and extending vertically along the plate from the top edge to a point somewhat above the bottom edge thereof, see Fig. 8. Rib 16 is preferably fixed to plate 15 by spot, or other type of, welding, but other forms of suitable fastening means may be used as desired. Secured to the upper face of each of plates 15, as viewed in Fig. 3, at a slight distance. inwardly of the left hand edge thereof, is a similar ver-i tical rib 17, similarly fixed to plate 15. Also similarly fixed to the same face of plate 15, and preferably at its mid-position longitudinally thereof, isa vertical rib 18 which is similar to ribs 16 and 17 except that a portion has been removed at the outer edge thereof, for a purpose later more fully explained. As the mold units are of identical construction, with the possible exception of the end ones at the front and rear of the clamping frame, which may have the ribs on the outer face omitted to facilitate the clamping operation if desired, only one of said units will be described in detail.

Extending longitudinally along the same side of the plate 15 as ribs 1618, adjacent its lower edge, and fitting into the angularly shaped bottom ends of ribs 16, 17 and 18, is a metal rib 19, of the same cross sectional size and shape as ribs 16 and 17, similarly fixed to the plate. Fixed by welding or otherwise to the same side of plate 15, to extend longitudinally along the top edge of the side face thereof, between vertical ribs 16 and 18, is a metal rib 20, triangular in cross-section, and having a flat face in engagement with the flat face of plate 15, so as to present an upwardly and outwardly inclined face presented downwardly toward the mold cavity for a purpose later more fully understood. Similarly fixed to the same side of plate 15, is a similar rib 21 extending between the top ends of vertical ribs 18 and 17, for a similar purpose for a second mold cavity.

Fixed to the lower face of plate 15, as viewed in Fig. 3, which will be hereinafter referred to as the second face thereof, are a number of metal ribs comprising vertical ribs 22 and 23 which are similar to ribs 16 and 17 of the first face described of plate 15, and similarly secured thereto but to project in the opposite direction. Also se-v cured to said second face of plate 15 is a vertically extending central rib 24 similar to rib 18 and similarly secured to the plate but to project in the opposite direction, as will be understood in Fig. 3. Also extending longitudinally along the second face of plate 15 adjacent its lower edge, and fitting into the angularly shaped bottom ends, of ribs 22, 23, and 24, is a nb 25. similar to rib 19.

on the first face of plate 15, and similarly fixed thereto but to project in the opposite direction. Also secured to. the second face of plate 15 to extend longitudinally along the top edge thereof between the top ends of vertical ribs 22 and 24 is a metal rib 26, similar to rib 20 on the first face but projecting in the opposite direction, and between the top ends of vertical ribs 24 and 23 extends a metal rib 27'similar to rib 21 on the first face but projecting in the opposite direction. As thus far described it is seen that ribs 16 and 22 are similar in construction and directly opposite each other on opposite sides of plate 15. The same is true of ribs 18 and 24, ribs 17 and 23, ribs 19 and 25, ribs 20 and 26, and ribs 21 and 27. This makes the ribs thus far described symmetrically arranged on opposite sides of the plate.

Welded, or otherwise suitably fixed, to the right hand angular face of vertical rib 22, as viewed in Fig. 3, is a vertical metal rib 28, square in cross-section, with one of its corner edges touching the plate 15 and with its opposite diagonal edge being free. It is pointed out that ribs 16, 17, 19, 22, 23 and 25 of the mold unit are preferably each one-half of a rib such as 28, cut longitudinally on a diagonal plane to form ribs triangular in crosssection and of the desired length. Welded, or otherwise suitably fixed, to the left-hand angular face of vertical rib 23, as viewed in Fig. 3, is a vertical metal square rib 29, similar to rib 28. Also welded, or otherwise suitably fixed, to the lower angular face of horizontal rib 25, as viewed in Fig. 8, is a horizontal rib 30, square in crosssection, similar to ribs 28 and 29 except longer and horizontal. The diagonal dimension of the cross-section of each of the square ribs 28, 29 and 30 is the same as the thickness of the slabs to be molded, and the altitude of each of the triangular cross-section ribs 16, 17, 19, 22, 23 and 25 in a direction perpendicular to the plate 15 is one-half the thickness of the slab to be molded. The

square cross-sectional ribs 28, 29 and 30 are each so fixed 'm A. A

face of horizontal rib 25,.as viewed in Figs. 6-8, is a horizontal metal rib 31, square in cross-section, similar to square rib 30 but smaller in size and extending horizontally from ribs 22, 28 to ribs 23, 29, to form a V-shaped groove in the bottom edge of each of the two slabs to be molded in the two mold cavities between each pair of adjacent plates 15. As seen in Figs. 6-8; the squaresection rib 31 is so positioned that one of its diagonal dimensions lies in a vertical plane also passing through one ofthe diagonal dimensions of square-section rib 30 so that ribs 25, 30 and 31 have a meeting longitudinal edge at the top of rib 30. This leaves a V-shaped notch or recess 32 adjacent the bottom of each mold unit on one side, between the horizontal rib 30 and one-half of the bottom of each of the vertical ribs 28 and 29, for a purpose later more fully explained.

For the purpose of forming a V-shaped groove in one of the vertical edges of each of the two slabs to be molded in each pair of assembled mold units, I have provided a pair of vertical metal ribs 33 and 34, each square in cross-section, these two ribs being rigidly fixed together longitudinally along two adjacent corners as by welding or other suitable fastening means. These two ribs are so secured together that a common vertical plane passes through the diagonal dimension of both, with said plane being midway between theadjacent faces of adjacent plates 15 and extending longitudinally thereof when the molds are assembled together in the frame. Ribs 33 and 34 thus form a rib unit which is insertable into and removable from the mold units when the mold units are not clamped together. As seen in Fig. 2 the unitary ribs 33, 34, are inserted between the central vertical ribs 18 and 24 of the mold unit when two adjacent mold units are placed together in the frame. When the mold units are clamped together the rib units 33, 34 are thus clamped between the vertical ribs 18 and 24. As also seen in Fig. 2, the right and left hand central protruding edges of unitary ribs 33, 34, fall in the same longitudinal, vertical, central plane as the upper longitudinal protruding edge of rib 31, thus providing for a continuous longitudinal and vertical groove in the bottom and one vertical edge of each of the slabs to be molded in the apparatus. In order toprovide clearance for the joined welded edges of the unitary ribs 33, 34, the apex portion of each of central, vertical ribs 18 and .24 has been removed. .As seen in Fig. 2, the inner angular faces of ribs 33 and 34 fit snugly against the side angular faces of ribs 18 and 24 to hold unitary ribs 33 and 34 firmly in place when the mold units are clamped together, but permit their removal when the mold units are separated after the concrete is hardened.

. .As will be understood in Figs. 2, 3 and 6-8, the mold units are assembled by first placing the first face of a mold unit against a back plate in the frame, or directly against the vertically extending brace members 2 of the frame, it being understood that the first mold unit thus placed in the frame may have the ribs omitted from its first face, a

if desired, so that that face of plate 15 is flat and may bear directly against the upright brace members 2. This first placed mold unit however will have the described ribs on its second face. All of the other mold units will have the described ribs on both faces of the plate 15, with the possible exception of the last mold unit placed in the frame, in which the ribs on the second face may be omitted to facilitate the operation of the clamping cams, or a separate clamping plate may be used as desired.

After the first mold unit is placed at the rear of the clamping frame, another mold unit will be added with its first face ribs engaging the second face ribs of the unit first placed. At this time the outer faces of ribs 16 and .17 engage the inner faces of ribs 28 and 29 respectively, and the end portions of the horizontal rib 19 will engage in their respective notch or recess 32. This centers or registers these two mold units together in proper '6 position, as will be understood in Figs. 2, 3 and 6-8. As these two units are being placed together, the unitary ribs 33, 34 will be placed in position, or they may be inserted downwardly into place after the two mold units have been brought into face engagement, as desired. The other mold units, and unitary ribs 33, 34, are then assembled in a similar manner, until the frame is filled. The mold units are then clamped together, and the frame vibrated while the molds are being filled with wet concrete through their open tops. As will be understood, suitable reinforcing elements will be properly placed in the mold cavities before the molds are filled with concrete.

When the concrete is hardened, the clamps are released, the clamping rods or cables 6 removed, and the mold units succesively separated. As earlier stated, the vertical unitary ribs 33, 34, and the horizontal, bottom, central ribs 31, form a continuous groove in the bottom edge, and one of the vertical edges, of the slab molded in each of the mold cavities, see Figs. 10 and 11. In the right-hand end portion of the right-hand mold cavity, when the mold units are assembled together, the vertical ribs 16 and 22 are so inclined as to form a tongue on the corresponding vertical slab edge, and in the left-hand end portion of the left-hand mold cavity, the vertical ribs 17 and 23 are so inclined as to form a tongue on the corresponding vertical slab edge, as will be understood in Fig. 2. The ribs 20 and 26 at the upper, inner edges of the mold cavities, are far enough apart to permit entry of the wet concrete through the top ofthe mold, and at the same time form beveled edges along the opposite corners of the top edge of the mold, as will be understood in Figs. 7 and 10. This, in effect, forms a tongue along the top edge of the slab, whose minimum width forms a flat portion 35, small enough to enter a sufficient distance into any one of the edge grooves of the slabs, when placed edge to edge, as seen in Fig. 10. This is because the diagonal dimension of each of the square ribs 31, 33 and 34, is greater than the width of the space, at the top, between the top ribs 20 and 26 of each mold cavity. This construction eliminates sharp edges on the grooves, which might easily become boken or crushed when handling the slabs.

As will be understood inthe drawings, in connection with the foregoing, when the concrete in the molds is hardened and the molds unclampe d, the molds units may be separated from each other and the tongue and groove slabs easily removed from the molds. This is because removal of one mold unit laterally from the adjacent mold unit removes the ribs of i the first face of plate 15 of one from the ribs of the second face of the other,

and leaves the hardened slabs in the two mold cavities free to be swung outwardly from the top, which will rock the portion behind the longitudinal square ribs 31 up wardly a slight distance until the top side edges of the slabs clear the outer edge of the beveled ribs 26 and 27, at which time the two slabs may be removed upwardly from the two mold cavities, and the unitary vertical ribs 33 and 34 removed from between the two slabs, or the slabs removed from these two ribs, as desired. As will be understood, the unitary vertical ribs 33 and 34 swing outwardly with the slabs during this initial movement, after which they and the two slabs are easily separable. The above slab removing operation will be readily understood from Figs. 2, 3 and 6-8.

Figs. 9-11 show four of the slabs made in the above identified apparatus, and laid flat on the ground, or elsewhere as desired, with adjacent tongues and grooves in engagement. While in the drawings I have shown the faces of the ribs at 45 degree angles with relation to the plates 15, his to be understod that other degree angles may be used if desired.

In Figs. 12-15, I have shown a slightly modified form of apparatus, with the slabs molded and hardened therein, for forming two edges of each slab with tongues and the other two edges as plain or flat, and also provisions 7 for enabling breaking the slabs into halves and quarters. In Figs. 12-15, I have indicated the metal ribs that are similar to those described in the first form, with corressponding numerals with a prime added, it being understood that, without further description, their function is the same as those in the previous form. (Instead of the central, vertical ribs of the previous form, I have in the present form provided a fiat, central, vertical, metal bar 36, having a rectangular cross-section of the shape shown at its top in Fig. 12, this cross-section remaining constant from its top to its bottom except as it decreases in width at the V-shaped bottom. Bar 36 is welded, or otherwise suitably fixed, at one edge to the second face of plate 15, to extend at right angles thereto a distance equal to the thickness of the slab to be molded, and acts as a separator between the two mold cavities to form a plain or flat edge at the corresponding ends of the mold cavities. As will be understood, this apparatus will provide for the pouring of the wet concrete through the open top of the molds, while the clamped molds are being vibrated, to form a pair of slabs, each having a horizontal tongue on its bottom edge and a vertical tongue along one of its vertical end edges, and a flat surface on the other two edges.

In order'to enable the hardened slabs to be broken into halves when desired, I have provided a vertical, metal score rib 37, triangular in cross-section, and welded, or otherwise suitably fixed, to the first face of the plate 15 along a line midway of the length of the slab, to form a breaking score 'channel 38 as seen in Fig. 16. Directly opposite scoring rib 37, is a metal score rib 39, similar in shape and position to score rib 37, and welded, or otherwise suitably fixed to the second face of plate 15' to project in a direction opposite to that of rib 37, as will be understood in Figs. 12 and 14. As. seen in Fig. 14, scoring ribs 37 and 39 extend from the open top of the mold to the bottom longitudinal ribs 19 and respectively, which latter they contact with similarly sloped surfaces. This provides for breaking the hardened slabs into halves when desired.

To provide for further breaking one of said half slabs into quarter slabs, I have added two horizontal ribs, 40 and 41, triangular in cross-section, welded, or otherwise fixed, the former to the first face of plate 15' and the latter to the second face thereof. Ribs 40 and 41 are directly opposite each other on opposite faces of the plate, and are positioned midway of the height of the mold cavity so as to provide score lines 42 for said quarter slabs, see Fig. 16. It is to be noted that ribs 411 and 41 do not extend quite as far from the surface of plate 15 as ribs 37 and 39. This is because ribs 40 and 41 being horizontal, the rib 40 of one mold unit must be spaced sufficiently far from rib 41 of the adjacent mold unit,

to permit the wet concrete to freely pass downwardly therebetween to the space therebelow as the mold is be ing filled, whereas ribs 37 and 39 are vertical and do not present such problem, for obvious reasons.

As will be understood, the various ribs could be of wood, or other material than wood or metal, in which case those ribs on opposite faces of plates 15 and 15" could be secured thereto by bolts or the like 43, and those ribs which are fixed to other ribs could be secured by nails or the like 44, as seen in Figs. 19 and 20.

Having described my invention, I claim:

Apparatus for forming tongue and groove concrete slabs, comprising, a plurality of similar mold units adapt ed to be clamped together side by side standing edgewise to form open-top molds, each of said mold units having a plate provided with a first face on one side and a second face on the other side, each of said first and second faces having vertical and horizontal ribs arranged to form mold cavities, each of said ribs being in cross section half of a square cut diagonally, the diagonally out side of each rib being fixed to its respective side face of the plate, and the perpendicular distance from the diagonally cut side to the apex of the rib being onehalf of the thickness of the slab to be formed, the ribs on the first face being respectively directly opposite those on the second face and extending in the opposite direction therefrom, a rib square in cross section and twice the size in cross section of each of the half square ribs, secured longitudinally along the outer side of one of the vertical ribs of the second face and having a beveled bottom end, a rib similar in cross section to the last mentioned square rib, secured longitudinally along the lower side of a horizontal rib of the second face and having beveled ends, said square ribs each being of a diagonal thickness equal to the thickness of the slab to be formed, whereby to provide means for registering the mold units when placing them side by side during assembling.

References Cited in the file of this patent UNITED STATES PATENTS 783,451 Morenus Feb. 28, 1905 1,045,411 Kenny Nov. 26, 1912 1,085,593 Cole Feb. 3, 1914 1,115,618 Tomlinson Nov. 3, 1914 1,273,168 Fergusen July 23, 1918 1,534,353 Besser Apr. 21, 1925 1,685,188 Beckwith Sept. 25, 1928 1,760,282 Pedersen May 27, 1930 1,925,733 Pandolfi Sept. 5, 1933 2,270,541 Martin I an. 20, 1942 r 2,545,029 Hemb Mar. 13, 1951 

